<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>3.3常用的CSS选择器</title>
  <style>
    p{
      background-color: cornsilk;
      line-height: 36px;
      text-indent: 12px;
    }
    .item {
      color: red;
    }
    #box {
      list-style-type: lower-roman;
    }
    ul {
      list-style-type: lower-greek;
    }
    ul.one{
      background-color: sandybrown;
    }
  </style>
</head>
<body>
  <p class="one">优先级：id选择器>类选择器>元素选择器</p>
  <h3>元素选择器</h3>
  <p>我是段落111</p>
  <p>我是段落222</p>
  <h3>类选择器</h3>
  <ul class="one">
    <li class="item">第一个子项</li>
    <li class="item">第二个子项</li>
    <li class="item">第三个子项</li>
  </ul>
  <h3>id选择顺</h3>
  <ul id="box">
    <li class="item">第一个子项</li>
    <li class="item">第二个子项</li>
    <li class="item">第三个子项</li>
  </ul>
</body>
</html>